AD644

Features:

Matched Offset Voltage
Matched Offset Voltage Over Temperature
Matched Bias Currents
Crosstalk 124 dB at 1 kHz
Low Bias Current: 35 pA max Warmed Up
Low Offset Voltage: 500 mV max
Low Input Voltage Noise: 2 mV p-p
High Slew Rate: 13 V/ms
Low Quiescent Current: 4.5 mA max
Fast Settling to 60.01%: 3 ms
Low Total Harmonic Distortion: 0.0015% at 1 kHz
Standard Dual Amplifier Pinout
Available in Hermetic Metal Can Package and Chip Form
MIL-STD-883B Processing Available
Single Version Available: AD544


Pinout




Description

The AD644 is a pair of matched high speed monolithic FET input operational amplifiers fabricated with the most advanced bipolar, JFET and laser-trimming technologies. The AD644 offers matched bias currents that are significantly lower than currently available monolithic dual BiFET operational amplifiers: 35 pA
max, matched to 25 pA for the AD644K and L, 75 pA max matched to 35 pA for the AD644J and S. In addition, the offset voltage is laser trimmed to less than 0.5 mV, and matched to 0.25 mV for the AD644L, 1.0 mV and matched to 0.5 mV for the AD644K, utilizing Analog Devices' laser-wafer trimming (LWT) process.

The tight matching and temperature tracking between the operational amplifiers is achieved by ion-implanted JFETs and laser-wafer trimming. Ion implantation permits the fabrication of precision, matched JFETs on a monolithic bipolar chip. This process optimizes the ability to produce matched amplifiers
which have lower initial bias currents than other popular BiFET op amps. Laser-wafer trimming each amplifier's input offset voltage assures tight initial match and superior IC processing guarantees offset voltage tracking over the temperature range. The AD644 is recommended for applications in which both excellent ac and dc performance is required. The matched amplifiers provide a low cost solution to true wideband instrumentation amplifiers, low dc drift active filters and output amplifiers for four quadrant multiplying D/A converters such as the AD7541, 12-bit CMOS DAC.